Multiple Influenza Virus Vaccine Vials ready for flu shot season

(© Sherry Young -

New research offers a surprising benefit from regularly receiving the flu vaccine each year.

HOUSTON — Vaccination against flu and pneumonia might reduce the risk of Alzheimer’s disease, according to new research presented this week at the virtual Alzheimer’s Association International Conference. Similar findings were presented by two different research groups at the conference.

The first study by researchers at the University of Texas Health Science Center at Houston (UTHealth), originates from an exploratory analysis of millions of medical records to identify factors associated with the risk of developing conditions like Alzheimer’s disease. After observing from these data that flu shots are correlated with a lower incidence of the disease, lead study author, Albert Amran, pursued further evidence of this relationship.

“Because there are no treatments for Alzheimer’s disease, it is crucial that we find ways to prevent it and delay its onset,” says Amran, a medical student at the McGovern Medical School at UTHealth, in a statement. “About 5.8 million people in the United States have this disease, so even a small reduction in risk can make a dramatic difference. We began our study by looking for ways we could reduce this risk.”

Amran’s team, in collaboration with researchers from the university’s School of Biomedical Informatics, used machine learning to analyze health records from more than 9,000 people over the age of 60. Scientists were looking for an association between seasonal flu vaccination and Alzheimer’s disease.

The group controlled for potentially confounding risk factors such as smoking status, obesity, diabetes, cardiovascular disease, education, age, and income.

The study finds that people with at least one flu vaccination are 17% less likely to be diagnosed with Alzheimer’s disease later in life. This association is even stronger in people who consistently got their flu vaccine, with an additional risk drop of 13%.

The findings also suggest that protection against Alzheimer’s disease is more strongly associated with people who had received their first documented flu shot at a younger age than those who were vaccinated later in life. For example, people who receive their first flu shot at 60 years old have a lower risk versus those who have their first vaccination at age 70.

Similar findings for pneumonia vaccine

The second study comes from researchers out of Duke University and the University of North Carolina. The group investigated the relationship between pneumococcal vaccination, with and without an accompanying seasonal flu shot, and Alzheimer’s risk. Their research uses health data from more than 5,000 participants, including some people with a known genetic risk factor for Alzheimer’s disease.

The analysis was adjusted for sex, race, birth cohort, education, smoking, and presence of the genetic risk factor.

Results show that receiving pneumococcal vaccination between ages 65 and 75 reduces the risk of developing Alzheimer’s disease by 25-30%. Non-carriers of the risk gene can are up to 40% less likely to develop the condition.

The total number of pneumonia and flu vaccinations received between ages 65 and 75 is also associated with lower risk for the disease. In contrast to the study performed at UTHealth, Ukraintseva and her team don’t see an effect with flu shot alone.

“Vaccinations against pneumonia before age 75 may reduce Alzheimer’s risk later in life, depending on individual genotype,” explains co-author Svetlana Ukraintseva in an Alzheimer’s Association release. “These data suggest that pneumococcal vaccine may be a promising candidate for personalized Alzheimer’s prevention, particularly in non-carriers of certain risk genes.”

Searching for the connection to Alzheimer’s disease

Both groups are currently investigating the possible biological mechanism to explain their findings.

“One of our theories of how the flu vaccine may work is that some of the proteins in the flu virus may train the body’s immune response to better protect against Alzheimer’s disease,” notes Amran. “Providing people with a flu vaccine may be a safe way to introduce those proteins that could help prepare the body to fight off the disease.”

Ukraintseva shares her thoughts in a statement to MedPage Today. “Some vaccines show beneficial off-target effects on health that span beyond the protection against specific disease,” she explains. “This could be because they may improve immunity on a broad scale.”

Researchers in both studies note that more research is necessary to investigate the association.

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About Judy Minkoff, PhD

Judy Minkoff holds her doctorate in immunology and molecular pathogenesis from Emory University. She has over a decade of experience in preclinical laboratory settings working on viruses and vaccine development. She was a medical writer for two-and-a-half years and has been a freelance science writer and editor since 2016.

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